Target support structure for pickup tubes



April 18, 1967 E. M. MUSSELMAN 3,315,109

TARGET SUPPORT STRUCTURE FOR PICKUP TUBES Filed Jan. 28, 1965 INVENTOR. @1 7. LZmv AKA/011mm BY United States Patent 3,315,109 TARGET SUPPORT STRUCTURE FOR PICKUP TUBES Elvin M. Musselman, Lancaster, Pa., assignor to Radio Corporation of America, a corporation of Delaware Filed Jan. 28, 1965, Ser. No. 428,685 3 Claims. (Cl. 313--65) This invention relates to support structures used in pickup tubes and particularly to a support structure for a relatively fragile target of a pickup tube of the image orthicon type.

Image orthicon tubes include a target structure supported on a metallic collar, which in turn is supported by a plurality of rods sealed through the envelope of the tube. The target structure comprises a metal ring supporting a target wafer made of glass or other material, and a metal mesh, in close spaced relation. The relatively high temperatures and flushing gases used in the manufacture of a tube of this type require that the operation of mounting the target structure on the support collar, be elfected after the collar has been fixed in the tube envelope and after the adjacent end of the tube envelope has been sealed.

Consequently, the mounting of the target upon the previously fixed collar must be efiected from a location remote from the collar, and has involved the insertion of the target structure through a relatively long neck portion at the other end of the bulb. Embossrnents have heretofore been provided on the support collar and target ring which were adapted to be forcefully brought into engagement by the application of an axial force of appreciable magnitude to the target structure during its extension through the neck portion aforementioned. Prior to a fully seated engagement of the embossments in response to the axial force referred to, the target was subjected to an appreciable radial stress that in many cases cracked or deformed the target wafer to such degree as to render it useless. Furthermore, the engagement between the embossments on the target ring and the support collar was sometimes unsatisfactory, thereby adversely affecting a continued desired positioning of the target structure in the tube.

Accordingly, it is an object of the invention to provide a target structure having features that contribute to freedom of the target from harmful stresses during a mounting of the target structure on its support.

A further object is to provide a target structure having means thereon for locking the structure to its support and wherein the locking means are sufiiciently flexible to be movable out of engagement with the support during a mounting operation, and are adapted to spring back into a positive and secure engagement with the target support, after the mounting operation.

One feature of the invention resides in a target structure having rectilinear spring members tangentially fixed to spaced portions of the outer periphery of the metal ring portion of the target structure. The outer diameter of the metal ring is made sufficiently smaller than the inner diameter of the target support, so that when the end portions of the spring members are deflected into engagement with the target ring, the target structure may be extended into desired position within the support collar without the application to the target structure of any force other than the negligible force required to deflect the spring members. The spring members may be made suificiently flexible so that the deflecting force is appreciably less than that required in prior practices and incapable of distorting the target wafer.

Another feature of the invention relates to the shape of the end portions of the spring members. Such end portions have a structure that complements the engaged portion of the support collar for providing a continued rugged and positive support of the target structure by the collar.

Further objects and features of the invention will become apparent as the present description continues.

In the drawing;

FIG. 1 is a plan view of a target structure and supporting collar in mounted position;

FIG. 2 is an enlarged sectional view line 2-2 of FIG. 1;

FIG. 3 is a perspective exploded View of the parts forming the structure of FIG. 1, and shows the target structure in spaced relation to and prior to its mounting on the target support collar;

FIG. 4 is a plan view of a spring element employed fOII retaining the target structure within its supporting co lar;

FIG. 5 is a sectional fragmentary view of a modified target support collar in engagement with a modified spring support element; and

FIG. 6 is a plan view of the modified spring support element.

One type of image orthicon pickup tube comprises a subassembly shown in FIG. 1. This subassembly includes a collar 10 having an opening 12 (FIGS. 1 and 3) in which is supported a target structure 14. The collar 10 constitutes one of several collars employed in a tube of the type discussed. The collars other than collar 10 are not shown in the drawing. The several collars, including collar 10, are supported in coaxial relation by a plurality of metal rods 16 having thereon an insulating tubing 13 and fixed to spaced portions of the outer periphery of the collar 10 by means of clamps 20 welded or brazed to the collars referred to. If desired, the rods 16 may be made of ceramic without a need for a tubing.

In the interests of simplicity, the target structure shown in FIGS. 1 and 3 has certain parts thereof removed, such as the target wafer and field mesh. However, a fragment of a complete target structure is shown in FIG. 2 and includes a metallic ring 19 having a shoulder 24 terminating in a cylindrical portion 26. The shoulder 24 forms an annular surface receiving a supporting member 25 for a relatively thin target wafer 28, made of glass, for example. Over the target wafer 28 is positioned a target mesh 39 suitably spaced from the wafer 28 by an annular spacing element 32. The periphery of the target mesh 30 may be suitably fixed to a mesh ring 27. A clamping system, comprising a spring 29, a retaining washer 31 and a welded strap 33, serves to retain both the target mesh and the target wafer in desired positions in the ring 19.

In the manufacture of a tube of the type under consideration, certain processing steps are followed which involve temperatures and atmospheres harmful to the target wafer 28.

Such steps are carried out after fixing the support collar 10 to support rods 16 in coaxial relation with other collars, not shown. To avoid harm to the target by the temperatures used, it has been the practice to mount the target structure 14, including the target wafer 28, upon the collar 10 after these steps have been completed.

Prior procedures, however, for mounting the target structure 14 on the support collar 10 upon completion of the manufacturing steps referred to, have not been completely satisfactory. This is because such prior procedures have involved a forced entry of the target structure into the support collar 10. Such forced entry has been accompanied by the application of appreciable radial compressive stresses to the target structure so that the taken along the relatively fragile target wafer 28 often cracked or otherwise became deformed.

The foregoing difficulty is avoided by the novel structure herein described. In this structure, the mounting means comprises a plurality of springs 34 normally rectilinear but adapted to be bent within their elastic limits into mounted positions. Each spring 34 is an elongated and relatively thin structure made of a suitable spring metal. In one example, as shown in FIGS. 1 to 4, the ends of the springs 34 are provided with V-like notches 36. The springs 34 are fixed to the outer periphery of the target ring 19 as by welding at intermediate regions 40 thereof (FIGS. 1 and 3). The springs 34 having lengths for receiving within their V notches 36 an inturned flange portion 38 of the support collar 10 while the springs are under some flexure as shown in FIG. 1.

To facilitate mounting the target structure 14 with the support collar 10, the outer periphery of the target structure is smaller radially than the inner periphery of the collar, to provide an annular space 42 (FIG. 1). This space has a radial dimension of sufficient magnitude for freely extending thereinto the target structure 14 when the springs 34 thereof have been flattened against the outer periphery of the target ring 19. A suitable tool (not shown) may be employed to hold the springs 34 against the periphery of the target ring 19 during a mounting of the target structure within the support collar 10. The tool may have movable engaging elements that may be moved first to engage end portions of the spring 34 for flattening such portions against the periphery of the target ring 19 during a mounting operation, and then to a location intermediate the spring ends to permit the springs to spring out and receive the inturned flange 38 in their notches 36, and also to allow removal of the tool.

For facilitating engagement between the springs 34 and the inturned flange 38, the notches 36 are preferably relatively widely flared at their free ends, as shown at 44 in FIG. 4. This assures desired register between the notches and the flange 38 without imposing a severe tolerance upon the axial positions of the target ring 19 and the flange 38 during a mounting operation. The side walls 46 of the notches are characterized by a gradually decreasing flare so that the side walls adjacent to the bottoms of the notches are only slightly flared. It is desirable that some flare in the side walls of the notches extend as far as the bottoms of the notches, to assure such firm engagement between the notches and the flange 38, that axial relative movements of the target structure 14 and the support collar 10 are effectively prevented. To further assure the absence of such relative movements, it is preferred that the thickness of the flange 38 be slightly greater than the width of the slots at their bottom portions.

A modified form of spring is shown in FIGS. and 6. In this form, a spring 48 is provided with tapered ends 50, 52. For receiving the tapered ends referred to, the collar is provided with a bipartite inturned flange having portions 54, 56 defining an annular slot having an angular configuration in cross-section in agreement with the tapered ends 50, 52 and having flat portions 51, 53. In this example, the outward pressure of the tapered ends of the spring 48 upon the groove-defining portions 54, 56 when the target structure 14 is mounted in collar 10 and the spring 48 is flexed in a manner similar to that shown in FIG. 1, is effective in combination with the flats 51, 53, to restrain axial relative movements of the target structure and collar.

To supplement the springs 34 or 48 in restraining transverse relative movements of the target structure 14 with respect to the collar 10, tabs 58 may be fixed as by welding to the flange 38 of collar 10 (FIG. 1). The tabs 58 extend inwardly of the collar 10 into close spaced relation to ring 19 and position the ring 19 in accurate concentric relation with respect to the collar 10.

I claim:

1. A target support structure for an image orthicon pickup tube comprising:

(a) a target structure including: 7

(l) a metal ring having an outer periphery of given diameter, and (2) a glass target wafer and a metal mesh supported in close spaced relation on said ring, (b) a metal collar having an inner periphery of larger diameter than said given diameter, and (c) a plurality of elongated "spring members having intermediate portions thereof fixed to said outer periphery of said ring, said spring members having end portions mechanically interlocked with said inner periphery of said collar. 2. A target support structure wherein,

(a) the inner periphery of said collar defines an annular groove, and

(b) the end portions of said spring members are tapered and extend into said annular grove.

3. A target support structure for an image pickup tube comprising:

(a) atarget structure including:

(1) a metal ring having an outer periphery of given diameter,

(2) a target wafer and a metal mesh supported in closely spaced relation on a portion of said ring across the opening thereof,

(b) an annular metal collar having an inturned flange,

and

(c) a plurality of elongated spring members fixed to said outer periphery of the metal ring and having free end portions, said free end portions having notches therein and urged into mechanical engagement with said inturned flange wherein said inturned flange is received by said notches,

((1) said inturned flange having an inner periphery of larger diameter than said given diameter, to provide an annular space between said ring and collar,

(e) said spring members when deflected against said ring having a smaller radial dimension than said annular space.

according to claim 1 and References Cited by the Examiner UNITED STATES PATENTS 2,582,843 1/1952 Moore 31367 X 3,249,785 5/1966 Floyd et al. 313-68 3,259,774 7/ 1966 Ney 31367 JAMES W. LAWRENCE, Primary Examiner.

R. SEGAL; Assistant Examiner. 

1. A TARGET SUPPORT STRUCTURE FOR AN IMAGE ORTHICON PICKUP TUBE COMPRISING: (A) A TARGET STRUCTURE INCLUDING: (1) A METAL RING HAVING AN OUTER PERIPHERY OF GIVEN DIAMETER, AND (2) A GLASS TARGET WAFER AND A METAL MESH SUPPORTED IN CLOSE SPACED RELATION ON SAID RING, (B) A METAL COLLAR HAVING AN INNER PERIPHERY OF LARGER DIAMETER THAN SAID GIVEN DIAMETER, AND (C) A PLURALITY OF ELONGATED SPRING MEMBERS HAVING INTERMEDIATE PORTIONS THEREOF FIXED TO SAID OUTER PERIPHERY OF SAID RING, SAID SPRING MEMBERS HAVING END PORTIONS MECHANICALLY INTERLOCKED WITH SAID INNER PERIPHERY OF SAID COLLAR. 